Field of the Invention
The present invention relates to a filter system for a vehicle, in particular a pre-filter system for a vehicle HVAC system.
Description of Related Art
Vehicles are regularly provided with dedicated HVAC (heating, ventilation, and air conditioning) systems, to control environment conditions within a vehicle cab, for the purpose of operator comfort.
An example outline of a known HVAC system configuration is provided in FIG. 2. A vehicle cab 100 is provided with a connected HVAC unit 102 which may comprise suitable blowers, condensers, evaporators, etc., necessary for regulation of the temperature in the interior 104 of the vehicle cab 100. The HVAC unit 102 is operable to draw in ambient air 106 from the exterior of the vehicle through inlet 108, for appropriate heating or cooling as required. An HVAC filter 110 is provided between the HVAC unit 102 and the ambient air 106, to prevent external debris from entering the HVAC unit 102. The exhaust air from the cab interior 104 is returned to the external environment via outlet 112.
A problem with the use of such a HVAC system, and in particular for agricultural use for example in tractors and harvesters, is that the external environment may contain high levels or dust or other debris, such as chaff. In such situations, the HVAC filter 110 is prone to frequent obstruction and possible blockage due to accumulated debris on the externally-facing side of the filter. In such situations, the performance of the HVAC system is negatively impacted until the filter can be cleaned of accumulated debris.
A known solution to this issue is to stop the vehicle, and to perform a manual cleaning of the HVAC filter 110, e.g. by an operator leaving the cab and directly accessing the filter surface. However, such an approach results in interruption to vehicle operating time, and a disruption of operator comfort.
An alternative solution is to reverse the direction of flow of the HVAC unit 102 such that the air flow direction in the system is reversed, to blow away any accumulated debris from the filter 110 surface. However, such action can require a relatively large air pressure to effectively clean the HVAC filer 110, which can result in increased energy consumption of the system. Furthermore, the HVAC operation is interrupted, which may result in disruption to operator comfort.
It is an object of the invention to provide a filter system for a vehicle HVAC system which addresses the above problems.